1. Field of the Invention
This invention relates generally to torque limiting tools, and more particularly to torque limiting tools that have at least one handle that provides a tactile response when a given torque value applied thereto is exceeded.
2. Description of the Prior Art
Torque wrenches, particularly torque wrenches which release at a predetermined torque level are well known in the art. Such torque tools or torque release tools are generally provided with some type of detent mechanism which permits the application of torque up to a given predetermined level above which level some type of tactile action takes place to alert the user that the torque level has been exceeded. It is also conventional to provide various types of adjustment means for varying the torque level at which the torque response occurs.
These tools have taken many different forms. For example, U.S. Pat. No. 2,918,834 shows a tool which has a roller adapted to engage a cam element that has two laterally displaced sections such that the roller must be positioned precisely in the handle so as to move from one section to the other; i.e. from one side of the cam to the other. This requires precision placing of the cam with respect to the axis of the roller to assure proper engagement. U.S. Pat. No. 3,577,815 shows a similar arrangement wherein a roller engages side pins and moves from the position between the pins to a position on top of the pins at a predetermined torque level. This arrangement also requires a precise positioning of the pins with respect to the roller axis so that the engagement is properly aligned and directional. U.S. Pat. No. 2,877,645 discloses a roller engaging an incline which is not a torque limiting tool but a torque indicating tool; i.e. the farther up the incline the more the torque and the more the registration of the torque on the gauge. U.S. Pat. No. 2,959,078 (reissued as U.S. Pat. No. Re. 25,547) discloses a roller engaging an inclined plane, the plane being asymetrical with respect to the central axis.
U.S. Pat. No. 4,316,397 shows a combination of rollers and balls which allow for adjustment of a handle to change the torque setting without changing the length of the handle. U.S. Pat. No. 3,633,445 decribes a torque limiting device wherein a ball is captivated between two closed cylindrical bores to provide the tactile action. U.S. Pat. No. 2,786,378 discloses another type of ball arrangement wherein the ball engages a tapered slot which can be varied in size.
U.S. Pat. Nos. 4,126,062; 3,599,515 and 4,532,836 all show various configurations of torque limiting wrenches wherein solid cylinders are utilized captivated between slots with the cylinder tilting to provide torque release.
These patents all have various drawbacks. For example, in the case of the patents which utilize the rollers, either the roller must be precisely aligned; i.e. radially within the tube so that the roller engages surfaces which are directioned in nature in order to operate, or the mechanism does not operate in such a manner as to snap tactilly at the predetermined torque level and return because of an unbalanced condition to the non-released position when the torque level is reduced below the given amount.
Therefore, it is a principle object of this invention to provide an improved torque release handle for a tool which allows assembly in an unconstrained rotative configuration and which will tactilly release at an adjustable level and return to the original position upon release of the torque force.